循环获取input.value

Question

I'm learning JS, and a little confused) I'm trying to select all elements in page by className, find in them input that have type=hidden , and take value of inputs to variable.

To be more clear I'll show demo html.

<div class="demo_class">
   <p>lorem ipsum</p>
   <input type="hidden" value="some-value">
</div>
<div class="demo_class">
   <p>lorem ipsum</p>
   <input type="hidden" value="some-value">
</div>
<div class="demo_class">
   <p>lorem ipsum</p>
   <input type="hidden" value="some-value">
</div>
<div class="demo_class">
   <p>lorem ipsum</p>
   <input type="hidden" value="some-value">
</div>

And there is some JavaScript

var container = document.getElementsByClassName("demo_class");
for (var i = 0; i < container.length; i++) {
    var inputValue = container[i].querySelectorAll("input[type=hidden]");
    container[i].insertAdjacentHTML(
        'afterbegin', 
        '<a href ="' + inputValue + '">Some text</a>'
   );
}

in this code I find all demo_class , in each of them find input[type=hidden] , but I cant do nothing with there value.. with code

inputValue.value there is undefined. Why? What I doing wrong?

I no need jQuery, want to learn JavaScript.

Answer 1

you don't get the value, but the element it self.

replace

var inputValue =   container[i].querySelectorAll("input[type=hidden]");

with

var inputValue =   container[i].querySelectorAll("input[type=hidden]")[0].value;

querySelectorAll() - Returs array of results (event if it find one element)

.value - Property to set/retrive the value of specific element

See here working example - here

Answer 2

I think that your problem depends on the DOMContentLoaded event, which isn't already fired when you exec your code...

 function ExampleCtrl() { 'use strict'; var self = this; self.hiddenInputs = document.querySelectorAll('[type="hidden"]'); self.result = document.getElementById('result'); for(var input, tpl, i = 0, len = self.hiddenInputs.length; i < len; i++) { input = self.hiddenInputs[i]; tpl = '<span class="key">'+ (i + 1) +'</span><span class="value">'+ input.value +'</span>'; self.result.innerHTML += '<h1>'+ tpl +'</h1>'; } } document.addEventListener('DOMContentLoaded', ExampleCtrl); 

 #result { padding: 1em .5em; } #result .key { font-weight: bolder; display: inline-block; padding-right: 2em; } #result .value { font-style: italic; } 

 <div class="demo_class"> <p>lorem ipsum</p> <input type="hidden" value="some-value"> </div> <div class="demo_class"> <p>lorem ipsum</p> <input type="hidden" value="some-value"> </div> <div class="demo_class"> <p>lorem ipsum</p> <input type="hidden" value="some-value"> </div> <div class="demo_class"> <p>lorem ipsum</p> <input type="hidden" value="some-value"> </div> <div id="result"> </div>